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WO2003003111A1 - Polarisation par champ electrique de matieres ferroelectriques - Google Patents

Polarisation par champ electrique de matieres ferroelectriques

Info

Publication number
WO2003003111A1
WO2003003111A1 PCT/GB2002/002956 GB0202956W WO03003111A1 WO 2003003111 A1 WO2003003111 A1 WO 2003003111A1 GB 0202956 W GB0202956 W GB 0202956W WO 03003111 A1 WO03003111 A1 WO 03003111A1
Authority
WO
WIPO (PCT)
Prior art keywords
sample
ferroelectric material
mask
poling
electric field
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/GB2002/002956
Other languages
English (en)
Inventor
Vasilis Apostolopoulos
Alessandro Busacca
Sakellaris Mailes
Robert Eason
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
University of Southampton
Original Assignee
University of Southampton
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by University of Southampton filed Critical University of Southampton
Priority to US10/481,902 priority Critical patent/US6952307B2/en
Publication of WO2003003111A1 publication Critical patent/WO2003003111A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/35—Non-linear optics
    • G02F1/355—Non-linear optics characterised by the materials used
    • G02F1/3558—Poled materials, e.g. with periodic poling; Fabrication of domain inverted structures, e.g. for quasi-phase-matching [QPM]
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/35—Non-linear optics
    • G02F1/37—Non-linear optics for second-harmonic generation
    • G02F1/377—Non-linear optics for second-harmonic generation in an optical waveguide structure
    • G02F1/3775—Non-linear optics for second-harmonic generation in an optical waveguide structure with a periodic structure, e.g. domain inversion, for quasi-phase-matching [QPM]

Definitions

  • the present invention relates to electric field poling of ferroelectric materials, particularly to a method of inducing periodic poling in surface regions of samples of ferroelectric materials, and to optical waveguide devices comprising ferroelectric materials having periodic poling in surface regions.
  • a particularly common technique is that of electric field poling, whereby an electric field is applied across a sample of ferroelectric material. This causes inversion of crystal domains in the material, which reverses the polarity and hence the nonlinearity.
  • the periodicity is achieved by applying a metal mask/electrode structure corresponding to the desired pattern of poling to a surface of the sample before applying the electric field. It is necessary to make very accurate calculations of the electric charge flowing during the poling process, as this governs the level of domain inversion achieved, and hence the quality of the resulting poled sample.
  • a first approach referred to as controlled spontaneous backswitching, has been applied to bulk samples of lithium niobate of typical thickness 500 ⁇ m, to create periods of 4 ⁇ m [3], and more recently 2.6 ⁇ m [4].
  • the applied electric field is rapidly modulated, which exploits a natural tendency of recently-inverted domains at the edge of inverted areas to return to their original orientation (backswitching).
  • backswitching the width of the inverted area reduces, altering the mark-to-space ratio of the poling.
  • a stabilisation voltage is applied to prevent further backswitching.
  • Uniform short period poling can be engineered in this way, but the complicated variation of the electric field requires complex voltage control and detailed calculations.
  • a further feature of the standard bulk electric field poling and the controlled spontaneous backswitching techniques is that they aim to produce poling through the whole depth of the sample.
  • the requirement for deep domain inversion is no longer important so long as there is a good overlap between the guided optical fields and the inverted domain regions.
  • Typical depth dimensions in the case of waveguides lie in the region of only about 2 ⁇ m to 10 ⁇ m.
  • poling techniques which aim to achieve uniform high quality domain engineering at depths exceeding this.
  • One technique which is addressed to creating shallow poling is based on Li 2 O out-diffusion [6]. This can cause superficial domain inversion, but cannot achieve deep enough domains for sufficient overlap with the guided optical fields used in waveguides. Furthermore, it requires high temperature annealing processes.
  • the present invention is based on the surprising result that it is possible to obtain high quality periodic poling by providing what, according to conventional bulk electric field poling techniques, would be regarded as too much charge.
  • the provision of too much charge to a sample being poled in this way produces undesirable "overpoling", in which the inverted regions grow too large and destroy the desired mark-to-space ratio of the poling. This makes the sample unsuitable for its intended nonlinear optical application, because the efficiency of the phase matching will be reduced.
  • overpoling results in the domain inversion of the entire sample so that no grating results.
  • a first aspect of the present invention is directed to a method of inducing a periodic variation of nonlinearity value in a sample of ferroelectric material, comprising: applying an electrically insulating mask to a surface of the sample, the mask defining a desired area of nonlinearity variation; applying an electric field across the sample to produce domain inversion in the sample beneath the area defined by the mask; and removing the electric field when non-inverted regions of the sample remain only in the vicinity of the surface of the sample beneath parts of the surface covered by the mask.
  • the non-inverted regions extend to a depth below the surface of the sample of less than 50 ⁇ m, less than 12 ⁇ m, or alternatively to a depth below the surface of the sample of between 2 and 10 ⁇ m.
  • F may have a value of between 1.3 and 10, or alternatively, of between 2_and 8, or alternatively, F may have a value greater than 2.
  • ferroelectric material may be one of lithium niobate, lithium tantalate, KTiOPO 4 ,
  • a third aspect of the present invention is directed to an optical waveguide fabricated from a sample of ferroelectric material as described in the preceding two paragraphs.
  • the waveguide may be a planar waveguide or a channel waveguide.
  • a fourth aspect of the present invention is directed to an optical device comprising an optical waveguide as described in the preceding paragraph.
  • the optical device may be configured for operation as one or more of: a forward three-wave mixing device; a backward three-wave mixing device; an optical parametric oscillator; a photon pair generator; a second harmonic generator; a power dependent switch; an electro-optic Bragg grating; or an acousto-optic Bragg grating.
  • a fifth aspect of the present invention is directed to an optical device comprising a 1 -dimensional or a 2-dimensional photonic band gap structure fabricated from a sample of ferroelectric material as described above.
  • Figure 1(a) shows a schematic representation of a bulk electric field poling method according to the prior art
  • Figures 1(b) and 1(c) show schematic representations of the electric field poling process according to the method of Figure 1(a);
  • Figure 2 shows a schematic representation of apparatus used to induce a periodic variation of nonlinearity in a sample of ferroelectric material in accordance with embodiments of the present invention;
  • Figures 3(a), 3(b) and 3(c) show schematic representations of the electric field poling process according to embodiments of the present invention
  • Figure 4 shows curves of the variation of voltage and current applied to a sample using the apparatus of Figure 3;
  • Figure 5 shows a graph of the relationship between domain period and domain depth measured from samples of ferroelectric material poled in accordance with embodiments of the present invention
  • Figures 6(a) and 6(b) show optical microscope pictures of a sample of ferroelectric material poled in accordance with an embodiment of the present invention
  • Figures 7(a) and 7(b) shows optical microscope pictures of channel waveguides fabricated in samples of ferroelectric material poled in accordance with embodiments of the present invention
  • Figure 8 shows a scanning electron microscope picture of a sample of ferroelectric material poled in accordance with an embodiment of the present invention
  • Figure 9 shows a scanning electron microscope picture of a sample of ferroelectric material poled in accordance with an embodiment of the present invention and having a submicron domain period
  • Figures 10 to 15 shows schematic plan views of waveguide devices fabricated from samples of ferroelectric material poled in accordance with embodiments of the present invention.
  • Standard bulk electric field poling of ferroelectric materials is a well- established technique which is typically used to pole congruently-grown wafers of crystalline lithium niobate and other materials.
  • the poling is carried out along the z-axis, which corresponds to the optic axis.
  • the basis of the standard technique is to apply an electrically-conducting mask defining the desired poling period to a surface of the sample.
  • the mask is applied to one of the z-faces, to give the required poling along the optic axis.
  • An electric field is applied across the sample to reverse the ferroelectric crystal domains, and hence the optical nonlinearity, only in the parts of the crystal under the areas covered by the mask, thus forming a poled grating structure extended through the full depth of the sample.
  • Figure 1(a) shows a schematic cross-section of a sample of ferroelectric material prepared for poling in this way.
  • the sample 10 has a pattern defined by a thin metal layer 12, such as 200 nm-thick aluminium, deposited on its +z surface.
  • a continuous layer of metal 14 is applied to the -z surface.
  • the two metal layers in effect form a pair of electrodes.
  • Each surface is then surrounded with an insulating medium 16, which may be liquid or gas, or a vacuum.
  • an insulating layer such as a layer of photoresist, can be deposited over the metal layer 12.
  • the features of the mask are arranged to be parallel to either the x or y axis of the sample; conventionally the y axis is used.
  • the sample After preparation, the sample is subjected to an applied electric field by connecting an external voltage source 15 across the electrode layers. This produces the desired poling. Reversal of the ferroelectric domains occurs when the applied field exceeds the so-called coercive field. This is a property of the material in question, and is about 220 kV cm "1 for lithium niobate. -11-
  • Figure 1(b) is a schematic diagram depicting the state of the sample 10 when poling is complete.
  • the standard bulk poling method seeks to provide 180° domains that extend throughout the crystal depth. In Figure 1(b), this is indicated by the arrows, with the downward pointing arrows corresponding to those parts of the sample underneath the metal mask and hence exposed to the electric field, and in which domain reversal has occurred.
  • the upward pointing arrows correspond to those parts protected by the insulating medium, which remain non-inverted.
  • the parts are well- defined, and the mark-to-space ratio of the inverted/non-inverted domains is constant throughout the sample depth.
  • the poling will be of poor quality.
  • F values typically smaller than 0.9 the sample will be "underpoled", because the calculated charge corresponds to inversion of a smaller domain volume than the region defined by the mask. In this case domains are inverted preferentially in areas where domain nucleation is easier, e.g. at the edges of the mask pattern or -12-
  • Figure 1(c) shows a sample 11 which has been overpoled.
  • the desired mark-to-space ratio of the poling is adversely affected. This is of particular significance for small grating periods, where the effects of any such error will be proportionately larger.
  • the present invention is based on the surprising result that is it possible to achieve high quality periodic poling with constant poling period by exploiting the apparently undesirable overpoling effect.
  • F is larger than about 2
  • the domain inversion readily spreads, causing merging between adjacent domain areas, so that the entire sample is inverted.
  • the sample appears uniformly poled when observed between crossed polarisers.
  • methods according to embodiments of the invention are suitable for creating inverted domains in the vicinity of the surface of samples of ferroelectric material. Using these methods it is possible to fabricate very good quality periodically poled regions that extend in the propagation direction over centimetre dimensions, but only extend to the requisite ⁇ 10 ⁇ m depth of waveguide structures.
  • FIG. 2 shows a schematic diagram of apparatus used for carrying out the poling method according to an embodiment of the present invention.
  • a lithium niobate sample 50 was prepared from a 500 ⁇ m thick, 3.5 inch diameter z-cut wafer supplied by Crystal Technology Inc (USA). The -z face of the sample was covered with SI 813 Shipley photoresist to a thiclcness of 1.2 ⁇ m using spin-coating. Photolithography was used to create an insulating mask corresponding to the desired periodic poling pattern, by exposing the photoresist to ultraviolet light through a periodic amplitude mask, and then developing it in the known manner.
  • the resulting relief pattern defined by the insulating mask allowed application of gel electrodes 54 to both the patterned area (-z face) and the +z face. The latter served as a uniform electrode for the application of the electric field. This was provided by a constant current high voltage source 56 connected via an external circuit 58 to the gel electrodes 54.
  • the poling pattern is defined by the mask of insulating photoresist; this is in contrast with the prior art method, in which a conductive mask is used. Use of a conductive mask does not permit surface domain structures to be engineered by overpoling. In further contrast with the prior art, the mask may be positioned on the -z face at any angle with respect to the x and y axes; alignment with either of these axes is not required. This simplifies the method of the present invention, and may allow poling of samples which would be rejected as unsuitable for poling with standard methods.
  • the sample was poled using a constant current configuration where the applied electric field was varied to keep the current constant, while the charge that flowed through the sample 50 was calculated by a -14-
  • Figure 3(a) shows the sample 50 at the point at which sufficient charge has been delivered to produce poling throughout the whole depth of the crystal, in much the same way as the desired end result of the prior art bulk poling process.
  • the inverted regions shown by the downward pointing arrows, are those parts exposed to the gel electrode 54, while the photoresist mask 54 insulates the underlying crystal from the electric field so that inversion is prevented (upward pointing arrows).
  • Figure 3(b) shows the sample 50 as overpoling commences, and the inverted regions begin to spread sideways and alter the mark-to-space ratio of the poling from that defined by the mask 52.
  • Figure 3(c) shows the sample 50 in its final poled state.
  • the inverted regions shown by the downward pointing arrows, extend through most of the sample. However, small non-inverted regions (upward pointing arrows) remain in the surface region of the sample 40 under those parts of the surface protected by the insulating mask 52.
  • the mask is believed to provide sufficient protection from the electric field such that these regions remain non-inverted for very high levels of overpoling, with values of F as large as even 100 or more expected to provide usable surface periodic poling. Such large values are not necessary, however; any value of F greater than about 2 should provide sufficient overpoling, and in some -15-
  • a value as low as 1.3 may be adequate. More typically, though, values of F between about 1.3 and 10, or, more usefully, between 2 and 8, will give the desired results.
  • Figure 4 shows a plot of a typical poling curve, that is, the variation of voltage (dotted curve) and current (solid curve) with time as measured on an oscilloscope. The single voltage pulse can be seen.
  • a range of periods have been successfully engineered using this method, in which photolithographic patterning via an amplitude mask is used to form the insulating mask. These include 2.5 ⁇ m, 3.5 ⁇ m, 4.0 ⁇ m and 6.4 ⁇ m. Longer periods of the order of 10 ⁇ m or 20 ⁇ m or above are also possible. However, it is not an easy task for conventional photolithography to reliably produce features extending far below 1 ⁇ m.
  • ultraviolet exposure of the applied photoresist layer can be performed interferometrically by using a phase mask instead of the amplitude mask discussed above.
  • interferometric exposure can be achieved using two beam interferometry. Other steps in the poling method are performed as described hereinbefore.
  • overpoling is particularly well- suited to the production of poled samples with sub-micron periods.
  • Standard bulk electric field poling tends to produce poor quality poling at these dimensions, because any errors caused by even slight overpoling are significant so that it is difficult to achieve narrow inverted domains of a constant width throughout the depth of the sample.
  • the present invention overcomes this; it has been found that at poling depths confined to surface regions by overpoling, the period of domain inversion is still well- defined by the period of the applied insulating mask. Also, by providing surface poling only, the effect of error is less important; there is no requirement to provide high accuracy over a large crystal volume.
  • the samples were etched using pure HF acid for durations between 30 min to 60 min in order to reveal the surface domain structures.
  • poled samples were cut and polished at an angle of 45° ⁇ 17-
  • Figure 5 shows a plot of the variation of measured domain depth d with the period ⁇ of the imposed photolithographic pattern.
  • the variation of measured domain depth (taken for between 30 and 100 periods) is rather large, two clear points emerge. Firstly, there is a minimum in the domain depth achieved. Secondly, the mean depth is seen to scale approximately linearly with period. For applications that require sub-micron periodicity, this is again a useful observation as overlap between the guided modes and domain inverted regions is a pre-requisite for efficient nonlinear interactions.
  • Figure 5 shows two fits to the measured data points: one includes the origin (0,0) as an implicit data point. The close agreement between these two gradients further confirms the approximate linearity stated above.
  • Figures 6(a) and 6(b) show pictures of a single sample having a period of 6.4 ⁇ m produced with an F value of 6.
  • the pictures were taken at different magnifications (x50 and xlOOO respectively), and show the uniformity of the poled structures at different scales.
  • Figures 7(a) and 7(b) show further optical microscope images, this time of samples having periods of 3.5 ⁇ m, and produced with F values of 6.
  • Figure 7(a) shows a sample in which the periodic poling is formed in a channel waveguide structure formed in the sample of lithium niobate prior to poling, by the titanium indiffusion technique.
  • Figure 7(b) shows a similar poled waveguide structure, formed in this instance by proton exchange. The images show that the electric field -18-
  • poling method of the present invention may be used with great success in lithium niobate treated in either of these ways. Indeed, both of these waveguides have been successfully used in second harmonic generation experiments, in which 850 nm light from a Ti:sapphire laser was frequency-doubled to a wavelength of 425 nm.
  • Figure 8 shows a scanning electron microscope picture of a sample obtained with an F value of 8. HF/HNO 3 acid etching has revealed that the poling is confined to the surface region, in this case to a depth of 6.4 ⁇ m. The period of the poling is 2.5 ⁇ m. From this result and other measurements it is evident that the domain depth is inversely related to the F value. In other words, as F is increased, the domain depth reduces.
  • the depth is affected by the period of the insulating mask.
  • F values a wide range of F values is expected to give useful structures. It is expected that use of very high F values (perhaps about 100 or higher) will give very narrow and shallow domain regions, with dimensions in the nanometre region.
  • Figure 9 shows a scanning electron microscope picture of a poled sample, etching of which revealed regular 1 ⁇ m domain patterns with domain widths of 0.5 ⁇ m. It is believed that this is the first ferroelectric sample having a near sub-micron domain period to be fabricated by any electric field poling technique.
  • the methods of the present invention are well-suited for the fabrication of poled volumes in planar and channel waveguide structures. These can be used for a wide variety of nonlinear optical applications, as shown in Figures 10 to 15.
  • Figure 10 is a schematic plan view of a waveguide device 100 having a periodically poled grating structure 102 fabricated within a channel waveguide 104.
  • a structure of this type is suitable for use as a frequency converter based on the -19-
  • BTWM backward-three-wave-mixing
  • a device based on BTWM typically requires a periodicity of the non-linear grating of less than 1 ⁇ m, in order to compensate for the large momentum mismatch between the counter-propagating waves. Therefore, the above-described poling methods are ideally suited for .the fabrication of such devices because of the ease and simplicity with which high quality sub-micron periods can be created by using a phase mask or two beam interferometry to expose the photoresist mask.
  • Figure 11 shows a similar channel waveguide device 200 having a grating 202, configured for forward-three-wave-mixing.
  • FTWM typically requires periods of tens of micrometres, so suitable waveguides can be fabricated via the methods of the present invention involving use of an amplitude mask to expose the photoresist.
  • optical filtering may be necessary to separate idler from signal and to suppress the residual pump signal. -20-
  • Figure 12 show an optical parametric oscillator (OPO) fabricated in the form of a waveguide device 300 having a periodic grating 302 in a channel waveguide.
  • the optical feedback required for oscillation is provided by reflectors 304 arranged at each end of the grating 302, such as Bragg gratings directly fabricated in the ferroelectric material.
  • OPOs are widely used as sources of coherent radiation possessing a very broad tunability range, which find useful application for example in spectroscopy, material and laser science.
  • FIG. 13 shows a further waveguide device in the form of a photon-pair generator, which operates via a special case of TWM.
  • the device 400 shown is based on a forward interaction, and comprises a Y-shaped channel waveguide 402 containing a grating 404 and a wavelength division multiplexer 406.
  • the pump beam ⁇ p enters the device, and interacting with the nonlinearity of the poled waveguide, provides amplification for photons originating from quantum noise.
  • Each pump photon is then split into a signal photon with wavelength ⁇ s and an idler photon with wavelength ⁇ j, which are separated by the multiplexer 406 and exit the device 400 along one or other arms of the Y of the channel waveguide 402.
  • the two photons represent a pair and possess special correlation properties, which exhibit non-local behaviour. This can be exploited for example in a quantum key distribution system where the photon pair generator would represent the light source.
  • Figure 14 shows another waveguide device 500 comprising a periodic grating 502 in a channel waveguide, and configured for operation as a second harmonic generator.
  • This device is another case of TWM (here considered in the forward direction).
  • Second harmonic generation is useful for the generation of new wavelengths by frequency-doubling the output of readily available powerful lasers.
  • FIG. 15 shows a further waveguide device 600, which is a power-dependent optical switch.
  • a channel waveguide 602 has two arms, joined at two places by 50:50 beam couplers 604 to form a Mach-Zehnder interferometer.
  • One of the arms is provided with a poled grating structure 606.
  • the nonlinearity provided by the periodic poling is cascaded, by which it is meant the incident pump beam at frequency ⁇ is frequency-doubled to 2 ⁇ and then converted back to ⁇ .
  • the pump wave acquires a power-dependent phase shift which is used in combination with the operation of the interferometer to implement power-dependent switching. If the power is high the signal will exit port P h igh, otherwise port P ⁇ ow .
  • Optical devices relying on any interaction which can be realised using a grating structure or structures can be fabricated.
  • bulk and waveguide devices incorporating electro-optic and acousto-optic Bragg gratings are possible.
  • the accurate submicron poling periods which can be readily achieved by the methods according to embodiments of the present invention mean that
  • PBG devices are artificially created structures that possess periodicity at the wavelength scale, and for which a modulation of dielectric constant (refractive index n) exists.
  • the regular (usually linear in period) structure will reflect specific wavelengths ⁇ so that "bandgaps" appear (often called “stop bands”) in the reflection or transmission spectra of the devices.
  • PBG devices can be constructed in one, two or three dimensions, but always have a periodic modulation of refractive index at a scale of ⁇ /2n. For example, in lithium niobate, for which n ⁇ 2.3, a periodicity of ⁇ 325 nm is required for operation at a wavelength of 1.5 ⁇ m. -22-
  • the insulating mask may be fabricated using any electrically insulating material from which a suitable pattern can be defined; the invention is not limited to the use of photoresist. Further, although the results described herein have been obtained from samples of congruent lithium niobate, it is expected that the methods may also be successfully applied to stoichiometric lithium niobate.
  • the invention is not limited to the poling of lithium niobate.
  • Other ferroelectric materials in particular lithium tantalate, KTiOPO (KTP), RTiOAsO (RTA), KTiOAsO 4 (KTA), RTiOPO 4 (RTP), BaTiO 3 and KNbO 3 can be engineered using the methods of the present invention. It is well known that these materials can be poled using conventional bulk electric field poling techniques.
  • the ferroelectric material may be a wafer or other sample having a single crystal structure, or it may be polycrystalline. This is an advantage over standard bulk poling techniques, in which the object of creating domain structures which extend right through the material limits the application of the techniques to single crystal samples.
  • the ferroelectric material may also be doped with a dopant material which has the effect of reducing the susceptibility of the ferroelectric to photorefractive damage.
  • Lithium niobate in particular is prone to photorefractive damage, an undesirable effect caused by incident light which reduces the efficiency of optical interactions occuring in the ferroelectric.
  • Various dopants can be added to the ferroelectric to improve its resistance to the damage.
  • Many metal oxides are suitable dopant materials, including
  • waveguide may be poled, including planar waveguides and channel waveguides.
  • the waveguide may be formed in bulk ferroelectric material, or it may be a surface waveguide in which the ferroelectric material is deposited as a layer on a substrate of the same or a different material, possibly in a ridge waveguide configuration.
  • the waveguide may of the buried kind, with a layer of ferroelectric material located below the waveguide surface at an appropriate depth for the poling process to form the periodic domain structure within it.

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  • Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Optical Modulation, Optical Deflection, Nonlinear Optics, Optical Demodulation, Optical Logic Elements (AREA)
  • Optical Integrated Circuits (AREA)

Abstract

Procédé permettant d'induire une variation périodique de non-linéarité dans un échantillon de matière ferroélectrique, qui consiste à appliquer un masque d'isolation électrique sur une surface de l'échantillon, à appliquer un champ électrique sur l'échantillon pour produire l'inversion de domaine dans l'échantillon et à supprimer le champ électrique lorsqu'il ne reste des régions non inversées de l'échantillon qu'à proximité de la surface de l'échantillon au-dessous de parties de la surface couvertes par le masque. Ce procédé peut être utilisé pour fabriquer des périodes de domaine précises de taille inférieure au micron ou plus grandes qui sont confinées dans une région de surface de la matière ferroélectrique, si bien que la matière polarisée peut être utilisée pour fabriquer des guides d'ondes plans pour des applications optiques non linéaires. En particulier, les périodes de taille inférieure au micron peuvent être exploitées dans la fabrication d'un ou plusieurs dispositifs à bande interdite photonique à une ou deux dimensions.
PCT/GB2002/002956 2001-06-27 2002-06-26 Polarisation par champ electrique de matieres ferroelectriques Ceased WO2003003111A1 (fr)

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US10/481,902 US6952307B2 (en) 2001-06-27 2002-06-26 Electric field poling of ferroelectric materials

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GBGB0115657.9A GB0115657D0 (en) 2001-06-27 2001-06-27 High quality surface engineering of domain structures in congruent lithium niobate single crystals
GB0115657.9 2001-06-27

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8054536B2 (en) 2007-06-11 2011-11-08 University Of Southampton Electric field poling of ferroelectric materials

Families Citing this family (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7002179B2 (en) * 2003-03-14 2006-02-21 Rohm Co., Ltd. ZnO system semiconductor device
JP4550837B2 (ja) * 2004-02-10 2010-09-22 テレフオンアクチーボラゲット エル エム エリクソン（パブル） 調整可能な装置
TWI340287B (en) * 2006-06-21 2011-04-11 Univ Nat Central Fabrication method of periodic domain inversion structure
US7405512B2 (en) * 2006-06-22 2008-07-29 Gooch And Housego Plc Acoustic transducers having localized ferroelectric domain inverted regions
GB0801322D0 (en) * 2008-01-24 2008-03-05 Univ Southampton Compensation for the gouy phase shift in quasi-phase matching
GB0802852D0 (en) * 2008-02-15 2008-03-26 Univ Southampton A process for poling a ferroelectric material doped with a metal
EP2202568B1 (fr) * 2008-12-26 2018-09-05 SCREEN Holdings Co., Ltd. Modulateur optique
JP5594192B2 (ja) * 2011-03-08 2014-09-24 住友大阪セメント株式会社 光変調器
US9599876B2 (en) * 2015-01-13 2017-03-21 Shimadzu Corporation Periodic polarization reversal electrode, periodic polarization reversal structure forming method and periodic polarization reversal element
JP6446518B2 (ja) * 2017-10-04 2018-12-26 日本碍子株式会社 波長変換素子の製造方法
CN111312832A (zh) * 2020-02-28 2020-06-19 中国科学院上海技术物理研究所 一种铁电畴定义的串联二维光伏电池及制备方法
JP7263285B2 (ja) * 2020-03-24 2023-04-24 日本碍子株式会社 高調波発生素子の製造方法

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0745883A1 (fr) * 1995-05-30 1996-12-04 Eastman Kodak Company Procédé d'inversion de domaines ferroélectriques par application d'un champ électrique

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6344921B1 (en) * 1999-02-22 2002-02-05 Almantas Galvanauskas Optical parametric amplifiers and generators in optical communication systems
US6433919B1 (en) * 2000-05-19 2002-08-13 Wisconsin Alumni Research Foundation Method and apparatus for wavelength conversion and switching
US6801356B2 (en) * 2000-11-09 2004-10-05 University Of Southampton Optical parametric devices and methods for making same
US20020171913A1 (en) * 2000-11-16 2002-11-21 Lightbit Corporation Method and apparatus for acheiving
CN1134090C (zh) * 2001-01-05 2004-01-07 南京大学 以超晶格为变频晶体的全固态红、蓝双色激光器
US6853671B2 (en) * 2001-06-13 2005-02-08 Intel Corporation Method and apparatus for tuning a laser with a Bragg grating in a semiconductor substrate
US6788727B2 (en) * 2002-06-13 2004-09-07 Intel Corporation Method and apparatus for tunable wavelength conversion using a bragg grating and a laser in a semiconductor substrate

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0745883A1 (fr) * 1995-05-30 1996-12-04 Eastman Kodak Company Procédé d'inversion de domaines ferroélectriques par application d'un champ électrique

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
BATCHKO R G ET AL: "BACKSWITCH POLING IN LITHIUM NIOBATE FOR HIGH-FIDELITY DOMAIN PATTERNING AND EFFICIENT BLUE LIGHT GENERATION", APPLIED PHYSICS LETTERS, AMERICAN INSTITUTE OF PHYSICS. NEW YORK, US, VOL. 75, NR. 12, PAGE(S) 1673-1675, ISSN: 0003-6951, XP000868305 *
SUGITA T ET AL: "Ultraviolet light generation in a periodically poled MgO:LiNbO/sub 3/ waveguide", 10TH INTERNATIONAL SYMPOSIUM ON OPTICAL MEMORY 2000 (ISOM 2000), HOKKAIDO, JAPAN, 5-8 SEPT. 2000, vol. 40, no. 3B, Japanese Journal of Applied Physics, Part 1 (Regular Papers, Short Notes & Review Papers), March 2001, Japan Soc. Appl. Phys, Japan, pages 1751 - 1753, XP002216478, ISSN: 0021-4922 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8054536B2 (en) 2007-06-11 2011-11-08 University Of Southampton Electric field poling of ferroelectric materials

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